The present invention relates generally to apparatus for determining various parameters of an acousto-optic (AO) or radio frequency (RF) system. More particularly, the present invention is directed to a calibrated signal-to-noise ratio (S/N) generator that can be used to evaluate the dynamic range and processing gain of a system.
In the testing of various acousto-optic or radio frequency systems, it is frequently desired to provide a simulated operating environment within which to evaluate the dynamic range or processing gain or both of the electronic system. In order to accurately evaluate such a dynamic range or processing gain in a laboratory environment, it is necessary to simulate two "real-world" signals and apply them simultaneously to the system under test. These "real world" signals are composed of a clean signal and a noise signal. The power levels of these two signals are independently adjusted to determine the greatest range between maximum and minimum power that the system can simultaneously process. Such a testing technique enables the user to test the response of an acousto-optic or RF system to real signal without leaving the laboratory.
It is also useful to be able to determine the processing gain of an acousto-optic correlator, that is, how far below the noise level the correlator can detect a common RF signal in both of its inputs. Such processing gain can be thought of as the dynamic range in the presence of excess noise. In addition, it would be useful to be able to determine the frequency resolution of such an acousto-optic correlator.